Dihalo dinitrocyclic ketones and process for producing same



DIHALO DINITROCYCLICKETONES AND PROCESS FOR PRODUCING SAME Henry Fener,Lafayette, Ind., and James W. Shepherd, Mars, Pa., assignors to PurdueResearch Foundation, Lafayette, Ind., a corporation of Indiana NoDrawing. Application June 14, 1956 Serial No. 591,507 a 14 Claims. (Cl.260586) Our invention relates to dihalo dinitrocyclic ketones and moreparticularly it relates to a,a'-dihal0-a,a'-dinltr0- cyclic ketones anda process for producing same.

In our application Serial No. 536,779, filed July 11, 1955, we havedescribed the production of dinitrocyclic ketones which are obtained inthe form of potassium salts and since the dipotassium dinitrocyclicketones are hygroscopic and not easily purified, we showed in our priorapplication that we can convert the dipotassium dinitrocyclic ketones toa, x,w,w'-tetrabromo-u,a-dinitr0- paraflins by brominating thedipotassium dinitrocyclic ketone under aqueous conditions.

We have now found that we can produce a,oL'-dih3.l0- a,a'-dinitrocyclicketones by halogenating the dipotassium a,a'-dinitrocyclic ketones underanhydrous conditions. ()ur new process can be illustrated by thefollowing equation:

NOr=C II I! where n is an integer from 1 to 5 inclusive, and X is ahalogen selected from the group consisting of chlorine and bromine.

Our new compounds are useful as intermediates in the production ofpolynitroparafiins compounds which are in turn useful as rocketpropellants. For example, 2,5-dibromo-2,5-dinitrocyclopentanone can be-reacted with methanolic hydrogen chloride to obtain dimethyl2-bromo-2-nitroglutarate and methyl-2,5-dibrorno-2,5- dinitropentanoate.

As indicated above, our new dihalo dinitrocyclic ketones are obtained byhalogenation of the corresponding dinitrocyclic ketone under anhydrousconditions. For purposes of our invention, we intend for the termhalogen or halo to include the compounds chlorine and bromine and theterm halogenation to include chlorination and bromination. Thus we canhalogenate dinitrocyclic ketones such as, for example,2,4-dinitrocyclobutanone, 2,5-dinit1'ocyclopentanone,2,6-dinitrocyclohexanone, 2,7- dinitrocycloheptanone, 2,8dinitrocyclooctanone, etc. under anhydrous conditions to obtain thecorresponding dihalo dinitrocyclic ketone products. Since thedinitrocyclic ketones are ordinarily obtained as the dipotassium salt,the starting material for our process is generally in this form. Sincethe dipotassium dinitrocyclic ketones are solid materials and since thehalogen is a liquid or gas, we ordinarily carry out our process in thepresence of an inert solvent such as ether, chloroform, carbontetrachloride, hexane, toluene, tetrahydrofuran, etc.

In carrying out our reaction for the production of our new compounds, weemploy temperatures below about C. in order to minimize side reactions.Preferably we employ temperatures of about -5 C. We also prefer toslowly add the halogen to the suspension of the dinitrocyclic ketone.Following addition of the halo tates Patent L "ice gen, the dihalodinitrocyclic ketone product can be recovered by any convenient means.to filter the reaction mixture, extract the solid residue with ether,evaporate the combined ether extract and filtrate from the reactionmixture in vacuo and recrystallize the solid product from carbontetrachloride.

The following examples are offered for purposes of illustration and wedo not tend to be limited to the particular materials, proportions, orprocedures shown.- Rather we intend to include within the scope ofthisapplication all equivalents obvious to those skilled in the art.

Example I A suspension of 6.25 grams of dipotassium2,5-dinitrocyclopentanone in 70 ml. of anhydrous ether contained in a3-neck flask, fitted with a glass stirrer, a pressure equalizingdropping funnel, and a reflux condenser topped with a calcium chloridedrying tube was cooled to 5;

Example 11 I Using the process of Example I except using chlorineinstead of bromine, the dipotassium salts of dinitrocyclobutanone,dinitrocyclopentanone, and dinitrocyclohexanone were converted to thecorresponding dichloro dinitrocyclic ketone.

Example III Using the process described in Example I, the dipotassiumsalts of dinitrocyclobutanone, dinitrocyclohexanone;dinitrocycloheptanone, and dinitrocyclooctanone were converted to thecorresponding dibromo dinitrocyclic ketone.

Example IV A solution of 8.3 g. of 2,5-dibromo-2,S-dinitrocyclopentanonein 40 ml! of methanoli'c hydrogen chloride was heated to reflux rapidlyand refluxed for 5 minutes. The reaction mixture was then cooled and theexcess solvent and hydrogen chloride evaporated in vacuo. The reactionmixture was then distilled under vacuo to obtain a fraction boiling at91 C. at 0.35 mm. Hg which fraction crystallized upon refrigeration. Thesolid material was recrystallized from hexane to obtain dimethyl2-bromo-2-nitroglutarate, M. P. 67.7-68.0 C. The distillation wascontinued to obtain a second frac tion at 127 C. at 0.35 mm. Hg n1.5120, for a 50.6% yield of methyl-2,5-dibromo-2,5-dinitropentanoate.

Now having described our invention, what we claim is:

1. Dihalo dinitrocyclic ketones having the following structural formulawhere X is a hologen selected from the group consist- 2.2,4-dibromo-2,4-dinitrocyclobutanone. 3.2,5dibromo-2,54initrocyclopentanone,

Ordinarily, we prefer The reac- 4. 2,6-dibromo-2,6-dinitrocyclohexanone.5. 2,S-dichloro-Z,S-dinitroeyclopentanone. 6.2,7-dibromo-2,Tdinitrocycloheptanone. 7. A processfor produeingrdihalodinitroeyclic ketones having the followingstructural formula 4 x rona 2xNO: N0:

7 0 where X is a hologen selected from the group consisting of' bromineand chlorine and where n is an integer from 1 to 5WhiC'h comprisesreacting a halogen selected from the group consisting of bromine andchlorine with a dipotassium dinitrocyclic ketone having the formulawhere n is an integer from 1 to 5 under anhydrous conditions.

8. A process for producing dihalodinitrocyc'lic ketones having thestructural formula where X is a halogen selected from the groupconsisting of chlorine and bromine and where n is an integer from 1 to 5which comprises reacting a halogen selected from the group consisting ofchlorine and brominevwith a dipotassium dinitrocyclic :ketone having theformula where -n -is an integer from 1 to 5 under anhydrous conditionsin the presence of an inert liquid medium.

9. A :process for producing a dibrorno dinitrocyclic ketone having thefollowing structural formula X 011;), X i Nbj o no,

EB-34, 10 an a r where X is a halogen selected from the group consist:ing of chlorine and bromine and where n is an integer from 1 to 5 whichcomprises reacting a halogen selected from the group consisting ofchlorine and bromine with a dipotassium dinitrocyclic ketone having theformula where n is an integer from 31 to 5 under anhydrous conditions inthe presence of an inert medium at a temperature below'about 10C.

10. A process for producing 2,4dibromo-2,4-dinitrocyclobutanone whichcomprises :reacting bromine with the dipotassium salt of2,4-dinitrocyclobutanone under anhydrous conditions in the presence ofan inert liquid medium at atemperaturebelow about 10" C.

ll. A process for "producing 2,5-dibromo-'2,S-dinitrocyclopentanonewhich comprises reacting bromine with the dipotassium salt of2,5-dinitrocyclopentanone under anhydrous conditions in the presence ofan inert liquid medium at a temperature below about 10 C.

12. A process for producing 2,6-dibromo-2,6-'dinitro cyclohexanone whichcomprises reacting bromine with the dipotassium salt of2,6-dinitrocyclohexanone under anhydrous conditions in the presence ofan inert liquid medium at a temperature below about 10' C.

13. A process for producing 2,7-dibromo-2fi-dinitrocyclohexanone whichcomprises reacting bromine with the dip'otassium salt of2,7-dinitrocycloheptanone under anhydrous conditions in the presence ofan inert liquid medium at a temperature below about 10 C.

14. A process for producing 2,6-dichloro-2;5-dinitrocye'lopentanonewhich comprises reacting chlorine with the dipotassium salt of2,5-dinitrocyclopentanone under anhydrous conditions in the presence ofan inert liquid medium at a temperature below about 10 C.

References Cited in the file of this patent UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent No 2,834,810 May 13, 1958 Henry Feueret a1.

It is hereby certified that error appears in the-printed specificationof the above numbered patent requiring correction and that the saidLetters Patent should read as corrected below.

Column 3, line 18, claim '7, line 38, claim 8, and'column 4, line 8,

claim 9, extreme right hand portion -of the formula, for "ZK each"occurrence, read 2K Signed and sealed this 4th day of November 1958SEAL) ttest:

KARL He MINE ROBERT c. WATSON Attesting Ofiicer Commissioner of Patents

1. DIHALO DINITROCYCLIC KETONES HAVING THE FOLLOWING STRUCTURAL FORMULA7. A PROCESS FOR PRODUCING DIHALO DINITROCYCLIC KETONES HAVING THEFOLLOWING STRUCTURAL FORMULA